The present invention is directed to integrated circuits. More particularly, embodiments of the invention provide high quality copper based capacitor that can be manufactured at low costs. Merely by way of example, embodiments of the invention have been applied to the fabrication of capacitors on integrated circuits characterized by a channel length of less than 130 nanometers. But it would be recognized that the invention has a much broader range of applicability.
Integrated circuits or “ICs” have evolved from a handful of interconnected devices fabricated on a single chip of silicon to millions of devices. Current ICs provide performance and complexity far beyond what was originally imagined. In order to achieve improvements in complexity and circuit density (i.e., the number of devices capable of being packed onto a given chip area), the size of the smallest device feature, also known as the device “geometry”, has become smaller with each generation of ICs. Semiconductor devices are now being fabricated with features less than a quarter of a micron across.
Increasing circuit density has not only improved the complexity and performance of ICs but has also provided lower cost parts to the consumer. An IC fabrication facility can cost hundreds of millions, or even billions, of dollars. Each fabrication facility will have a certain throughput of wafers, and each wafer will have a certain number of ICs on it. Therefore, by making the individual devices of an IC smaller, more devices may be fabricated on each wafer, thus increasing the output of the fabrication facility. Making devices smaller is very challenging, as a given process, device layout, and/or system design often work down to only a certain feature size.
One of the challenges in manufacturing IC has been to produce high quality capacitor within integrated circuits. As an essential element for many integrated circuits, capacitors and the manufacturing process thereof have been a challenge for fabrication laboratories. The capability and reliability of capacitors in the past have been related to physical dimensions. As the size of integrated circuits becomes smaller, the manufacturing of capacitors becomes increasingly difficult.
In the past, various conventional techniques have been developed for fabricating capacitors. For example, metal-insulator-metal (MIM) type capacitors have been fabricated for various applications using conventional techniques. Unfortunately, these techniques have been inadequate.
Therefore, it is desirable to have an improved technique for manufacturing capacitors for integrated circuits.